This article sheds new light on a crucial moment in the emerging Christological controversy. Among the key developments that occurred between 360 and the early 380s, the Christological debate between Apollinarius of Laodicea and Diodore of Tarsus made a significant, though largely misunderstood, impact on the Christological works of Gregory of Nazianzus. The article first characterizes the main Christological concerns of Apollinarius and Diodore and identifies the points of contention between them. It then gives a new interpretation of Gregory’s relationship to this debate. It argues, finally, that Gregory Nazianzen defines his Christology chiefly in opposition to Diodore, rather than to Apollinarius, as is commonly believed, even as he opposes them both in the end.

1. FN11) I use the term “Trinitarian” to indicate the theological position adopted by these theologians, as distinct from “pro-Nicene,” which indicates an ecclesiastical alliance and commitment to the Council of Nicaea as a conciliar standard, which could be interpreted in different ways by different theologians. See further Christopher A. Beeley, Gregory of Nazianzus on the Trinity and the Knowledge of God: In Your Light We Shall See Light. Oxford Studies in Historical Theology (New York: Oxford University Press, 2008), 10n27 and passim.

4. FN44) See, e.g., the current critical edition and most recent English translation: Paul Gallay, Sources chrétiennes 208 (1998) and Lionel Wickham, trans. On God and Christ: The Five Theological Orations and Two Letters to Cledonius (Crestwood: St Vladimir’s Seminary Press, 2002).

5. FN55) In their statements against Apollinarius, Basil and Damasus both refer to him as ‘one of their own.’ Basil, Ep. 92; Damasus, Il. sane 83. Apollinarius’ major extant work, the Detailed Confession of the Faith, dates from 358 to 362, or possibly 363. See Spoerl, “Apollinarius on the Holy Spirit,” 571–92.

6. FN66) See esp. Kelly McCarthy Spoerl, “A Study of the Κατὰ Μέρος Πίστις by Apollinarius of Laodicea,” (Ph.D diss., University of Toronto, 1991); “Apollinarius and the Response to Early Arian Christology,” Studia Patristica 26 (1993): 421–27; “Apollinarian Christology and the Anti-Marcellan Tradition,” Journal of Theological Studies (1994): 545–68; “Apollinarius on the Holy Spirit,” Studia Patristica 37 (2001): 571–92; following the seminal works of Lietzmann, Raven, and Muhlenberg.

7. FN77) Apollinarius, Kata Meros Pistis, 1, 6, 12. A good portion of this work, which begins with an anti-Arian statement of faith, is aimed at countering what Apollinarius perceives to be Marcellus’ denial of the distinction between the Father and the Son. Apollinarius’ works are cited according to the edition of Hans Lietzmann, Apollinaris von Laodicea und seine Schule: Texte und Untersuchungen (Tübingen: Mohr Siebeck, 1904).

14. FN1414) Greg.Naz. Ep. 101.30–31. References to Gregory’s works follow the Sources Chrétiennes editions. The letter’s second anathema, against the idea that the Son was “channeled” through the Virgin, is arguably directed against Diodore, not Apollinarius.

15. FN1515) Greg.Naz. Ep. 102.

16. FN1616) Greg.Naz. Ep. 202.9–13.

17. FN1717) Greg.Naz. Ep. 202.15–16.

18. FN1818) Apollin. Frag. 24–34.

19. FN1919) Apollin. Frag. 31.

20. FN2020) Apollin. Frag. 33.

21. FN2121) Apollin. Frag. 32.

22. FN2222) Gregory of Nyssa, Antirrh. (GNO 3/1, 148). On Apollinarius’ exegetical work in the Apodeixis and Gregory of Nyssa’s response, see Rowan Greer, “The Man from Heaven: Paul’s Last Adam and Apollinaris’ Christ,” Paul and the Legacies of Paul, ed. William S. Babcock (Dallas: Southern Methodist University Press, 1990), 165–182.

23. FN2323) Apollin. Frag. 163; Ep. ad Dion 7.

24. FN2424) Apollin. Frag. 10, 93. The terms ἕνωσις and κρᾶσις occur together in Origen, Cels. 3.41. In defense of the Christian belief that Jesus is himself the divine Word of God and also born of a mortal body, Origen writes, ‘his mortal body and the human soul in him received the greatest elevation not only by communion (κοινωνία) but by union and intermingling (ἕνωσις καὶ ἀνακράσει), so that by sharing in His divinity he was transformed into God’ (Chadwick trans.). While the precedent of Origen is more important, the terms of mixture also have currency in Stoic and Neoplatonic philosophy/physics: see Verna Harrison, “Some Aspects of St. Gregory the Theologian’s Soteriology”, Greek Orthodox Theological Review 34 (1989): 13, with bibliography.

33. FN3333) A series of Italian synods under Damasus of Rome likewise opposed Apollinarius, and may have had an influence on Gregory Nazianzen’s understanding of the same. See Beeley, Gregory of Nazianzus, 31–3, 318.

34. FN3434) In the Kata Meros Pistis and the De Unione, and in certain Fragments, Apollinarius speaks in terms of a two-part anthropology (flesh and soul), so that Christ is the Word made flesh, without a human soul or spirit (Apollin. KMP 2, 11, 28, 30; De Unione 12; Frag. 19, 22, 28, 41, 72, 129). In other Fragments we also find a three-part anthropology: the Word took on a human soul and flesh, without a human mind (see Apollin. Frag. 22, 25, 89, 91). Whether this difference reflects a substantive change of anthropological model or simply the further clarification of the same basic view is unclear. The fact that, at a relatively early point in Apollinarius’ career, his associates signed the Alexandrian Tome of 362, which denounces the view that Christ is ἄψυχος (Athanasius, Tome 7), supports the latter view.

35. FN3535) Or a mind plus soul and flesh. ἄνθρωπος νοῦς ἔνσαρκος ὤν. Apollin. Frag. 69; see also 70–2. It would be worth exploring to what extent Apollinarius’ anthropology reflects Origen’s idea that human beings are rational beings incarnated in human bodies—minus the now-scandalous theory of their pre-existence.

36. FN3636) Apollin. Frag. 70.

37. FN3737) Apollin. Frag. 74: ‘If together with God, who is intellect, there was also a human intellect in Christ, then the work of the incarnation is not accomplished in him’; see also 70–1.

38. FN3838) Apollin. Frag. 108, 117; see also 109.

39. FN3939) Apollin. Frag. 87; see also 42.

40. FN4040) Apollin. Frag. 9, 42.

41. FN4141) Apollin. Frag. 45: ‘He is not a human being but is like a human being, since he is not consubstantial with humanity in his highest part’; see also 69.

42. FN4242) Apollin. Frag. 91: ‘If we are made up of three parts [human mind, soul, and flesh], while he is made up of four [divine mind, plus a human mind, soul, and flesh], then he is not a human being but a man-God’ (οὐκ ἄνθρωπος ἀλλὰ ἀνθρωπόθεος). Apollinarius also observes that, just as we are both consubstantial with irrational animals (in the flesh) and not consubstantial with them (being rational creatures), so too is Christ consubstantial with us (in the flesh) and not consubstantial with us (having a divine rather than a human Logos) (Frag. 126).

43. FN4343) Apollin. Frag. 38.

44. FN4444) At Jesus’ conception in the Virgin, the Word spiritually performed the function of the life-giving substance, taking the place of the male seed, which thus became Jesus’ divine mind (Apollin. De Unione 13; see also 1).

45. FN4545) Apollin. Frag. 9, 85; see also KMP 31: we worship the Trinity, not the Trinity plus the man Jesus.

46. FN4646) Apollin. De Unione 5; Frag. 129; see also 123.

47. FN4747) Apollinarius is no doubt basing himself on a certain reading of Paul’s argument in Rom 7—that the law of sin in his members (or in his flesh, v. 18) is at war with the spiritual law of his mind, his ‘inmost self,’ where he ‘delights in the law of God’ (7.22–3)— combined with other New Testament passages that speak of the opposition between the flesh and the spirit, esp. Rom 8.1–17; 1 Cor 15.35–58; Gal 5.16–26; 6.8, 21; 1 Jn 2.15–16.

48. FN4848) Apollin. Frag. 74.

49. FN4949) Apollin. Frag. 76.

50. FN5050) Apollin. KMP 2.

51. FN5151) Apollin. Frag. 74; see also KMP 31.

52. FN5252) Apollin. KMP 2.

53. FN5353) Although ‘the Divinity took up the flesh’s capacity for suffering’ (Apollin. KMP 2; see 29), the Divinity remains without change and God power in the Word suffered no limitation in the incarnation: ‘whatever sufferings might come to the flesh, the Power of God had its own proper freedom from them’ (Apollin. KMP 11; see De Unione 6, 8), and ‘his mind is untrammeled by the sufferings of spirit and flesh (Apollin. KMP 30; see also Frag. 93, 117). On this point Apollinarius and Diodore are ironically closer to one another than either is to Gregory, who prefers a more radically theopaschite approach to the identity and work of Christ.

54. FN5454) For the evidence of Diodore’s career, see John Behr, The Case Against Diodore and Theodore: Texts and their Contexts. Oxford Early Christian Texts (Oxford: Oxford University Press, 2011), 48–52.

56. FN5656) It was most likely Diodore who nominated Flavian as Meletius’ successor in Antioch (veiled references can be found in Gregory’s De vita sua 1546–7, 1566–9, 1583–8)—for which he was excommunicated by a Roman synod the following year, for violating the prior arrangement for Meletius’ succession (Sozomen, HE 7.11; Socrates, HE 5.23)—as well as Nectarius as Gregory Nazianzen’s successor in Constantinople (Socrates, HE 7.8). For a reconstruction of the events of the council, see Beeley, Gregory of Nazianzus, 44–54. Gregory’s De vita sua = Carm. 2.1.11. References are to Gregory of Nazianzus, Autobiographical Poems, ed. and trans. Carolinne White, Cambridge Medieval Classics 6 (Cambridge: Cambridge University Press, 1996): 111–53.

59. FN5959) According to Julian’s disparaging Ep. 55 to Photinus. Julian himself and Gregory Nazianzen both studied there.

60. FN6060) According to Jerome, Diodore’s exegesis reflects his initial study under Eusebius of Emessa (bp. 341 to before 359), whom Jerome credits with (presumably Antiochene-style) literal exegesis (De vir. ill. 91)—who may himself have been a Eusebian, who was invited but declined to fill the see of Alexandria when Athanasius was deposed in 339.

61. FN6161) The stark contrast between Alexandrian and Antiochene Christology, as seen through fifth-century lenses, is no longer tenable as it is usually presented in the textbooks of early Christian doctrine. Nevertheless, Diodore is clearly a formative influence on a distinct tradition of Christological reflection which it still makes sense to call Antiochene at least through Nestorius.

71. FN7171) A point initially made by Rowan A. Greer in his seminal study “The Antiochene Christology of Diodore of Tarsus,” Journal of Theological Studies 7 (1966): 327–41.

72. FN7272) Diod. BD 6; see also SD 11.

73. FN7373) Diod. BD 17.

74. FN7474) Diod. BD 18.

75. FN7575) Diod. BD 24.

76. FN7676) Diod. BD 9–10.

77. FN7777) As the preceding sections on the incorruptibility of Jesus’ body also indicate. Diod. BD 7–8.

78. FN7878) See also Diodore’s treatment of Luke 2.52: it was the flesh, not the Word, which grew in stature and wisdom, as the Divinity gradually conferred wisdom on the body of Jesus. Diod. SD 2. See also BD 4: the man born of Mary did not exist before the heavens and the earth, like the Word; the one who is of Abraham was not before Abraham; and the son of David is not the maker of David and the creator of all things; BD 13: it was the man born of Mary who was under the Law, circumcised, and raised as a Jew (Gal 4), not the eternal Son of God; Diod. BD 16: the one who promised the thief that he would be with him in paradise must have been the divine Word, since the thief could not have remained with the man Jesus who was about to die and be buried, for ‘it is impossible that he, as dead, was buried, and that he, as living, led the thief into paradise’; and ST 7: Christ would receive from the Holy Spirit knowledge of things to come. Diodore’s statement in SD 4—‘The Lord, while he was in the womb of the Virgin and of that essence, did not have the honor of sonship, but when he was formed and became the temple of God the Word’—is so extreme that its authenticity may be questioned.

79. FN7979) It may be further observed that, if anything, Diodore is operating with a Logos-anthropos structure, not a Logos-sarx one, as Grillmeier supposed. See Grillmeier, Christ in Christian Tradition (1975), 353.

80. FN8080) Diod. BD 14. Diodore does not appear to have considered the parallel implication that, being only in the ‘form’ of God, the Word was also not himself God.

81. FN8181) Diod. BD 19.

82. FN8282) Diod. BD 1: ‘the flesh, of which the blessed Mary was the mother’; see also BD 22.

98. FN9898) Diod. BD 30: ‘We do not say two [sons] of one Father, but that the divine Word is a single Son of God by nature, and that he who is of Mary is by nature of David, and by grace of God. We add this, however: the two are one Son’; see also BD 31–3.

99. FN9999) Ibid.

100. FN100100) Diod. SD 2.

101. FN101101) Diod. BD 1.

102. FN102102) That Diodore considers Jesus’ humanity to be soteriological significant is clear (BD 18: the blood of the son of Mary cleanses the human race through suffering; see also BD 7 and 16), and he may well be the proximate source of the robust atonement theory found in Theodore and Nestorius. But soteriological arguments do not come into play in the debate with Apollinarius, who likewise (though differently) considers Jesus’ humanity soteriologically significant; nor does Diodore’s soteriology appear to match that of Gregory Nazianzen and, following him, most of later orthodox Greek tradition.

103. FN103103) Diod. BD 2.

104. FN104104) Diod. BD 19.

105. FN105105) Diod. BD 20; see also 26: the Word is ‘outside’ all the affairs of the incarnation, remained without change throughout, and therefore should not be said to be mixed with human existence. For related points, see SD 2: the Word did not grow in stature and wisdom (Lk 2.52); and SD 11: Christological cross-references must be avoided because the Word is not mortal.

106. FN106106) Grillmeier suggests that Diodore may have pursued a two-subject Christology in order to protect the divinity of the Word from the compromises implicit in the traditional communicatio idiomatum during the attacks of Julian, who ridiculed the human weaknesses of Christ. See Grillmeier, Christ in Christian Tradition (1975), 353–4. This suggestion seems to me tenuous.

107. FN107107) Greg.Naz. De vita sua, 607–31.

108. FN108108) Greg.Naz. Carm. 2.1.12 72–82 (De seipso et episcopis); De vita sua, l. 596. Basil of Caesarea, once an associate of Meletius, had recently died on 1 January 379. Before his death in 373, Athanasius rejected communion with Meletius in favor of the rival Antiochene community around Paulinus. On the synod’s connection with Damasus’ Italian synods of the 370s, see Beeley, Gregory of Nazianzus, 31–3.

109. FN109109) Reported in Damasus’ Letter to the Eastern Bishops (Theodoret, HE 5.10) and further developed in the Illut sane (Lester L. Field, Jr., On the Communion of Damasus and Meletius: Fourth-Century Synodal Formulae in the Codex Veronensis LX, with Critical Edition and Translation, Studies and Texts 145 [Toronto: Pontifical Institute of Mediaeval Studies, 2004]: 16–18), which became part of the dossier of documents that Damasus sent to Meletius’ synod of 379 for ratification.

110. FN110110) In Or. 22.12 Gregory offers a simple Trinitarian confession as a rallying point for the various groups: ‘a single test of piety, the worship of Father, Son and Holy Spirit, one Divinity and power in the three.... Once this has been defined, we shall reach agreement on all other points as well.’ On Gregory’s Trinitarian doctrine, see Beeley, Gregory of Nazianzus, chap. 3.

111. FN111111) Greg.Naz. Or. 22.4. Gregory’s orations are cited by oration and section number according to the SC editions, where available, and otherwise to Migne.

112. FN112112) Based on its connection with the synod of 379 and its anti-Apollinarian commission of Gregory, I will refer to Diodore’s Christology as “Antiochene.” Although we cannot assume that all contemporary Antiochenes agreed with Diodore, the consensus represented at the synod and Diodore’s rapid ascent in the new religious establishment justify calling his position Antiochene at this point. At the same time, I do not assume that all Antiochenes share the same view.

113. FN113113) This description is Gregory’s own (see also Greg.Naz. Ep. 101.12, 32–55) and does not match Diodore’s initial complaints against Apollinarius. It will later be taken up, however, by Gregory of Nyssa, in the Antirrheticus, who takes Gregory Nazianzen’s position in a more Antiochene direction.

115. FN115115) Greg.Naz. De vita sua, 632–4: ‘But they [the Antiochenes] make a similar mistake, in the opposite way, who unthinkingly posit two sons, one from God and the other from the Virgin.’

116. FN116116) Greg.Naz. De vita sua, 1146–89.

117. FN117117) Greg.Naz. De vita sua, 1184–5: ‘Those who say that the one of earth was a second son, or that the one who is saved is not complete, but lacks a human mind.’

118. FN118118) On the immediate occasion of the attempted Apollinarian takeover, see Greg.Naz. Ep. 101.12; 102.4.

119. FN119119) Greg.Naz. Ep. 101.2–11. He mentions their ‘outrageous teachings’ only in passing: Greg.Naz. Ep. 101.2, 6, 11. In Ep. 102 it is Gregory who is being interrogated (102.1), and in Ep. 202 Gregory’s immediate concern is with the Apollinarians’ ecclesiastical activities (202.7), which he attempts to thwart by means of doctrinal argument.

124. FN124124) Greg.Naz. Ep. 101.16b. The use of the term σωλήν (‘pipe’ or ‘channel’) with reference to Mary is rare, and does not appear to be Apollinarian. Epiphanius reports, with striking similarity, the Gnostic teaching that Jesus ‘brought down his body from above, passing through Mary the Virgin like water through a pipe’ (Panar. GCS 25:396.10; see also 388.10; 419.25). The Gnostic association further reinforces the Antiochene provenance of the idea, since the Gnostics had been regarded as teaching two sons since at least Irenaeus (whom Apollinarius probably read), much as Gregory now regards Diodore.

125. FN125125) Greg.Naz. Ep. 101.16a, 17.

126. FN126126) Greg.Naz. Ep. 101.16–29.

127. FN127127) Greg.Naz. Ep. 101.30–31.

128. FN128128) Greg.Naz. Ep. 101.33–74.

129. FN129129) For a summary view of Gregory’s Christology, see Beeley, Gregory of Nazianzus, chap. 2.

130. FN130130) Greg.Naz. Or. 29.19.

131. FN131131) Gregory anathematizes those who deny that Christ’s birth from Mary is ‘the birth of God’ (γέννησις Θεοῦ, Ep. 101.17); all agree that the Son is begotten of the Father.

132. FN132132) Greg.Naz. Or. 37.2; see also 25.15–16.

133. FN133133) Greg.Naz. Ep. 101.13–14. Along with Apollinarius, the phrase is also used Christologically by Irenaeus (Adv. haer. 3.16.3) and Eusebius of Caesarea (Dem. evang. 4.15.48; 4.16.8). It does not appear as such in Athanasius, Basil of Caesarea, or Gregory of Nyssa.

141. FN141141) Gregory’s single-nature language for Christ is most visible in the framework that governs the exegetical discussions of the fourth Theological Oration (in Or. 29.18–19 and 30.20–1; for an individual exegetical example, see 30.16).

142. FN142142) Almost without exception, Gregory speaks of two natures when he is describing the elements from which Christ was composed, as distinct from Christ’s current state as God-made-human. See, e.g., Ep. 101.19. Notably anti-Antiochene examples include Or. 37.2 (quoted above); De vita sua, 651; and Carm. 1.2.1.149–54.

143. FN143143) On Gregory’s use of two-nature constructions for Christ, and his use of nature-language in general, see Beeley, ‘Cyril of Alexandria and Gregory Nazianzen: Tradition and Complexity in Patristic Christology,’ Journal of Early Christian Studies 17.3 (2009), 381–419.

144. FN144144) The Son did not merely operate (ἐνεργεῖν) in Christ by grace, as in a prophet, but he ‘was and is joined together [with human existence] in his essence (κατ’ οὐσίαν συνάπτειν),’ Greg.Naz. Ep. 101.22. See also Or. 30.21: the Son divinizes human nature not by grace but by his assumption of it. Gregory make a similar qualification with regard to Christ’s relation to God the Father: Christ’s ‘receiving’ things (e.g., life, judgment, and glory) from the Father refers not only to his humanity, but also to his Divinity, since he receives his Divinity by reason of his nature, not grace (Or. 30.9).

145. FN145145) For a detailed account of Gregory’s practice of single-subject Christological exegesis, including a consideration of those passages that seem to contradict this approach, see Beeley, “Gregory of Nazianzus on the Unity of Christ,” in Peter Martens, ed., In the Shadow of the Incarnation, Essays on Jesus Christ in the Early Church in honor of Brian E. Daley, S.J. (South Bend: University of Notre Dame Press, 2008), 97–120.

146. FN146146) Greg.Naz. Or. 29.19–20. See also Greg.Naz. Ep. 101.14–15: ‘One and the same God and Son’ became human—‘the same one passible in flesh, impassible in Divinity, limited in body, unlimited in spirit, earthly and heavenly, visible and discerned spiritually, finite and infinite; so that by the same one, entirely human and God, the entire human existence, which fell under sin, might be fashioned anew.’

147. FN147147) Greg.Naz. Or. 37.2. For an account of this practice throughout Gregory’s career, see Beeley, “Gregory of Nazianzus on the Unity of Christ,” 99–102, 109–10.

148. FN148148) See, e.g., Greg.Naz. Or. 14.2; 31.2.

149. FN149149) Greg.Naz. Or. 22.13.

150. FN150150) Greg.Naz. Or. 45.28.

151. FN151151) Greg.Naz. Ep. 101.36–45.

152. FN152152) Greg.Naz. Ep. 101.52.

153. FN153153) Greg.Naz. Ep. 101.51.

154. FN154154) Greg.Naz. Ep. 101.32.

155. FN155155) Gregory’s usual term for completeness, ὅλος (see Ep. 101.15), is not Diodore’s (τέλειος); he does not speak of Christ’s consubstantiality with human flesh, as Diodore does; and his discussion of the relationship between perfect things (τέλεια) that are divine and human in Ep. 101.36–45 stems rather from Apollinarius’ argumentation. Nevertheless, Gregory repudiates Apollinarius’ denial that Christ is ‘complete (τέλειος) God and complete human being’ (Frag. 42).

156. FN156156) See also Greg.Naz. Or. 22.13; De vita sua, 607–31. The earlier Or. 2.23 may reflect later editing.

166. FN166166) Above all in the Antirrheticus. Gregory of Nyssa shares certain unitive elements with Gregory Nazianzen, such as the language of mixture; however, in other ways he departs from his Cappadocian colleague: He does not take up the Apollinarian term ‘one and the same’; he distinguishes between Christ’s composite part and non-composite part (Greg.Nyss. Antirrh. [GNO 3.1, 153; see also 218]); and his most conspicuous borrowing from Gregory Nazianzen is the anti-Apollinarian argument that the Word and a human mind are not mutually exclusive (Greg.Nyss. Or. cat. 11; Antirrh. 2 [PG 45.1128b]).

167. FN167167) On Gregory’s profound impact on Cyril of Alexandria’s Christology, see Beeley, “Cyril of Alexandria and Gregory Nazianzen.”